Zebra chip disease of potato Candidatus Liberibacter solanacearum is a serious pest of potato in the Americas and New Zealand. In November 2016 it was detected on potatoes for the first time anywhere in the EU by Spanish authorities in the autonomous region of Cantabria.
The disease is difficult to distinguish from other diseases affecting potato. Symptoms in above ground plant parts include stunting, chlorosis and purpling of foliage, upward rolling and scorching of leaves and the production of aerial tubers. Fresh tubers may appear healthy, but often have brown or pink coloured collapsed stolons. On cutting, there may be patchy discolouration of tuber tissue but this is often indistinct or absent. Characteristic symptoms can often be seen in fried potato tubers. These include irregular dark brown streaking of tuber tissue giving rise to the name ‘zebra chip’.
Raw and fried potato slices infected with zebra chip.
Zebra chip symptoms in potato. Leaf curl and discoloration.
Photos courtesy of Joe Munyaneza USDA/ARS